10.3.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are “Enable” and “Disable”.
The operation of PQSS can be described with a module diagram. All the modules in the
diagram are explained in the next sections.
GUID-91ED3E3D-F014-49EE-B4B0-DAD2509DD013-ANSI V1 EN
Figure 530: Functional module diagram
10.3.4.1 Phase mode setting
PQSS is designed for both single-phase and polyphase ac power systems, and selection
can be made with the Phase mode setting, which can be set either to the "Single Phase" or
"Three Phase" mode. The default setting is "Single Phase".
The basic difference between these alternatives depends on how many phases are needed
to have the voltage variation activated. When the Phase mode setting is "Single Phase",
the activation is straightforward. There is no dependence between the phases for variation
pickup. The PICKUP output and the corresponding phase pickup are activated when the
limit is exceeded or undershot. The corresponding phase pickup deactivation takes place
when the limit (includes small hysteresis) is undershot or exceeded. The PICKUP output
is deactivated when there are no more active phases.
However, when Phase mode is "Three Phase", all the monitored phase signal magnitudes,
defined with Phase supervision, have to fall below or rise above the limit setting to
Section 10 1MAC059074-MB A
Power quality measurement functions
1042 615 series ANSI
Technical Manual
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